The present invention is directed to a high-temperature superconductor of the system Bi--Sr--Ca--Cu--O.
Bednorz and Mueller disclosed superconductors based on lanthanum-strontium-copper oxide that have a high transition temperature of the transition from normal conduction into superconduction that was hitherto never achieved. Transition temperatures achieved for yttrium-barium-copper oxide systems lie at 70 through 90 K. Another system, bismuth-strontium-calcium-copper oxide recently has been disclosed and is currently under intensive investigations. The influence of the sintering parameters such as sintering temperature, sintering duration and partial oxygen pressure during the sintering process have been investigated.
The manufacture of the material cited second above proceeds based on the pulverization of initial nominal materials that are mixed, ground and cold-pressed. The sintering ensues in microprocessor-controlled furnaces, whereby the material is placed on zirconium oxide plates. Sintering temperatures that are applied when sintering in air lie at 800.degree., 860.degree., 880.degree., 900.degree. C., whereby the sintering is performed for a duration of ten hours.
Gold contacts are applied to the resultant materials for measuring the electrical properties. The magnetic properties of a respective material are identified by measuring the inductivity of a coil that surrounds the material.